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DTC U0401:68 [DC-DC CONVERTER (Mazda M Hybrid)]

id140206302200

Outline

System malfunction location

Error signal received from PCM

Detection condition

•  The DC-DC converter (Mazda M Hybrid) receives an error signal from the PCM.

Precondition

•  1.5 s have elapsed after the ignition was switched ON (engine off or on)

•  Voltage at DC-DC converter (Mazda M Hybrid) terminal 1A is 9-16 V for a continuous 1 s

Fail-safe

•  Inhibits the i-stop control.

•  Inhibits the non-power generation control.

•  Inhibits regenerative braking by the integrated starter generator (ISG).

•  Inhibits motor assist control by the integrated starter generator (ISG).

Possible cause

•  PCM malfunction

•  DC-DC converter (Mazda M Hybrid) malfunction

System wiring diagram

•  Not applicable

Connector diagram

•  Not applicable

System malfunction location	Error signal received from PCM
Detection condition	• The DC-DC converter (Mazda M Hybrid) receives an error signal from the PCM. Precondition • 1.5 s have elapsed after the ignition was switched ON (engine off or on) • Voltage at DC-DC converter (Mazda M Hybrid) terminal 1A is 9-16 V for a continuous 1 s
Fail-safe	• Inhibits the i-stop control. • Inhibits the non-power generation control. • Inhibits regenerative braking by the integrated starter generator (ISG). • Inhibits motor assist control by the integrated starter generator (ISG).
Possible cause	• PCM malfunction • DC-DC converter (Mazda M Hybrid) malfunction
System wiring diagram	• Not applicable
Connector diagram	• Not applicable

Diagnostic Procedure

Step

Inspection

Results

Action

1

RECORD VEHICLE STATUS WHEN DTC WAS DETECTED TO UTILIZE WITH REPEATABILITY VERIFICATION

•  Record the snapshot data.

Note

•  Recording can be facilitated using the screen capture function of the PC.

—

Go to the next step.

2

INSPECT FOR OTHER RELATED DTCs

•  Perform the DTC inspection for the DC-DC converter (Mazda M Hybrid).
(See DTC INSPECTION.)

•  Are any of the following DTCs displayed?

―  U0073:00

―  U0100:00

―  U212B:00

―  U3000:49

Yes

Repair the malfunctioning location according to the applicable DTC troubleshooting.

(See DTC U0073:00 [DC-DC CONVERTER (Mazda M Hybrid)].)

(See DTC U0100:00 [DC-DC CONVERTER (Mazda M Hybrid)].)

(See DTC U212B:00 [DC-DC CONVERTER (Mazda M Hybrid)].)

(See DTC U3000:49 [DC-DC CONVERTER (Mazda M Hybrid)].)

No

Go to the next step.

3

VERIFY PCM DTC

•  Perform the DTC inspection for the PCM.
(See DTC INSPECTION.)

•  Are any DTCs displayed?

Yes

Repair the malfunctioning location according to the applicable DTC troubleshooting.

(See DTC TABLE [PCM (SKYACTIV-G (E))].)

(See DTC TABLE [PCM (SKYACTIV-X)].)

No

Go to the next step.

4

INSPECT PCM FOR MALFUNCTION DEPENDING ON REPEATABILITY

•  Install/connect the part removed/disconnected during the troubleshooting procedure.

•  Clear the DTC recorded in the memory.
(See CLEARING DTC.)

•  Switch the ignition off, then ON (engine off).

•  Perform the DTC inspection for the DC-DC converter (Mazda M Hybrid).
(See DTC INSPECTION.)

•  Is the same Pending DTC present?

Yes

Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error.

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].)

If the CAN communication is normal, perform the diagnosis from Step 1.

•  If the malfunction recurs, replace the PCM.
(See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITH CYLINDER DEACTIVATION (E))].)

(See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (E))].)

(See PCM REMOVAL/INSTALLATION [SKYACTIV-X 2.0].)

Go to repair completion verification 1.

No

Go to the next step.

5

INSPECT PCM FOR MALFUNCTION DEPENDING ON REPEATABILITY AGAIN

•  Perform the "Action for Non-repeatable Malfunction" procedure.
(See TROUBLESHOOTING PROCEDURE [(E)].)

•  Perform the DTC inspection for the DC-DC converter (Mazda M Hybrid).
(See DTC INSPECTION.)

•  Is the same Pending DTC present?

Yes

Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error.

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].)

If the CAN communication is normal, perform the diagnosis from Step 1.

•  If the malfunction recurs, replace the PCM.
(See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITH CYLINDER DEACTIVATION (E))].)

(See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (E))].)

(See PCM REMOVAL/INSTALLATION [SKYACTIV-X 2.0].)

Go to repair completion verification 1.

No

The system is normal. (Explain to the customer that a malfunction was detected temporarily, but the vehicle is currently normal.)

Go to repair completion verification 2.

Repair completion verification 1

VERIFY THAT VEHICLE IS REPAIRED

•  Install/connect the part removed/disconnected during the troubleshooting procedure.

•  Clear the DTC recorded in the memory.
(See CLEARING DTC.)

•  Switch the ignition off, then ON (engine off).

•  Perform the DTC inspection for the DC-DC converter (Mazda M Hybrid).
(See DTC INSPECTION.)

•  Is the same Pending DTC present?

Yes

Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error.

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].)

If the CAN communication is normal, perform the diagnosis from Step 1.

•  If the malfunction recurs, replace the DC-DC converter (Mazda M Hybrid), then go to the next step.
(See DC-DC CONVERTER (Mazda M Hybrid) REMOVAL/INSTALLATION.)

No

Go to the next step.

Repair completion verification 2

VERIFY IF OTHER DTCs DISPLAYED

•  Perform the DTC inspection.
(See DTC INSPECTION.)

•  Are any other DTCs displayed?

Yes

Repair the malfunctioning location according to the applicable DTC troubleshooting.

No

DTC troubleshooting completed.

Step	Inspection	Results	Action
1	RECORD VEHICLE STATUS WHEN DTC WAS DETECTED TO UTILIZE WITH REPEATABILITY VERIFICATION • Record the snapshot data. Note • Recording can be facilitated using the screen capture function of the PC.	—	Go to the next step.
2	INSPECT FOR OTHER RELATED DTCs • Perform the DTC inspection for the DC-DC converter (Mazda M Hybrid). (See DTC INSPECTION.) • Are any of the following DTCs displayed? ― U0073:00 ― U0100:00 ― U212B:00 ― U3000:49	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC U0073:00 [DC-DC CONVERTER (Mazda M Hybrid)].) (See DTC U0100:00 [DC-DC CONVERTER (Mazda M Hybrid)].) (See DTC U212B:00 [DC-DC CONVERTER (Mazda M Hybrid)].) (See DTC U3000:49 [DC-DC CONVERTER (Mazda M Hybrid)].)
2		No	Go to the next step.
3	VERIFY PCM DTC • Perform the DTC inspection for the PCM. (See DTC INSPECTION.) • Are any DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [PCM (SKYACTIV-G (E))].) (See DTC TABLE [PCM (SKYACTIV-X)].)
3		No	Go to the next step.
4	INSPECT PCM FOR MALFUNCTION DEPENDING ON REPEATABILITY • Install/connect the part removed/disconnected during the troubleshooting procedure. • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Switch the ignition off, then ON (engine off). • Perform the DTC inspection for the DC-DC converter (Mazda M Hybrid). (See DTC INSPECTION.) • Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].) If the CAN communication is normal, perform the diagnosis from Step 1. • If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITH CYLINDER DEACTIVATION (E))].) (See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (E))].) (See PCM REMOVAL/INSTALLATION [SKYACTIV-X 2.0].) Go to repair completion verification 1.
4		No	Go to the next step.
5	INSPECT PCM FOR MALFUNCTION DEPENDING ON REPEATABILITY AGAIN • Perform the "Action for Non-repeatable Malfunction" procedure. (See TROUBLESHOOTING PROCEDURE [(E)].) • Perform the DTC inspection for the DC-DC converter (Mazda M Hybrid). (See DTC INSPECTION.) • Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].) If the CAN communication is normal, perform the diagnosis from Step 1. • If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITH CYLINDER DEACTIVATION (E))].) (See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (E))].) (See PCM REMOVAL/INSTALLATION [SKYACTIV-X 2.0].) Go to repair completion verification 1.
5		No	The system is normal. (Explain to the customer that a malfunction was detected temporarily, but the vehicle is currently normal.) Go to repair completion verification 2.
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED • Install/connect the part removed/disconnected during the troubleshooting procedure. • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Switch the ignition off, then ON (engine off). • Perform the DTC inspection for the DC-DC converter (Mazda M Hybrid). (See DTC INSPECTION.) • Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].) If the CAN communication is normal, perform the diagnosis from Step 1. • If the malfunction recurs, replace the DC-DC converter (Mazda M Hybrid), then go to the next step. (See DC-DC CONVERTER (Mazda M Hybrid) REMOVAL/INSTALLATION.)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTCs DISPLAYED • Perform the DTC inspection. (See DTC INSPECTION.) • Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification 2		No	DTC troubleshooting completed.